Bat Emergence at Old Tunnel State Park

Old Tunnel State Park in Fredericksburg may be the smallest state park in Texas. It consists of only 16.1 acres of land, but this park offers you nature’s unique experience: watching a colony of Mexican free-tailed bats emerge from the abandoned railroad tunnel.

Two Worlds Treasures visiting the Old Tunnel State Park in Fredericksburgh, TX.

The Old Tunnel State Park is home to up to 3 million Mexican free-tailed bats (Tadarida brasilienses mexicana) and 3,000 cave myotis (Myotis velifer) from May through October. They migrated each year to and from Mexico.

The sign by the lower viewing area at the Old Tunnel State Park, Fredericksburg, TX.

During emergence, the bats spiral upwards in a counter-clockwise direction in order to gain altitude. “It’s like a tornado,” the park ranger told us. When we went there, we got a chance to sit at the lower viewing area. It’s the closest one to the tunnel, where you can listen to an educational program about bats.

The ranger explains about the bats at the Old Tunnel State Park.

The Bat Emergence at Old Tunnel State Park

At first, we hardly saw them emerge until they flew higher and higher passed the tree line. Some of them flew above us. But, we’ve been warning to stay calm and didn’t make any noise due to their sensitivity to noise disturbance. Whenever we put our hands behind ears, we could hear their tiny wings flapping better. It was truly an unusual experience.

The bats at Old Tunnel State Park started to emerge.
It’s hard to capture them with a camera and it’s even harder to see them when they first emerged.

The bats emerge every night and travel as high as 10,000 feet and 60 miles, one-way. They’re feeding on agricultural pests such as cotton bollworms, cutworms, and webworm moths. Each bat can eat its weight in insects nightly. And, the Old Tunnel State Park colony may devour over 25 tons of moths per night! The farmers around Hill Country are happy because bats helped them kill the pests.

On the other hand, there are predators waiting for the bats. Aerial predators, such as red-tailed hawks, are sometimes seen catching bats as they emerge. While the terrestrial predators, such as raccoons, feed on fallen bats. Not to mention owls and snakes.

Viewing the Bat Emergence at Old Tunnel State Park

The best time to enjoy the bat emergence is from May through October. There are three options:  viewing the emergence from the upper viewing area, participating in a lower viewing area, or making special group tour reservations for your adult or youth group.

Upper Viewing Area

Adjacent to the parking area, it is open nightly from May through October. Bats are best viewed from this area during August and September when the emergence times are earlier and more lights are present. Sometimes people can see red-tailed hawks feeding on emerging bats.

No fees needed for this area but the park only allows 250 visitors each time. When they reach the limit, they will close off the parking lot next to the upper viewing area and will admit more visitors as people leave. Park opens at 5 p.m. and can reach the limit quickly, especially on high visitation weekends, like Memorial Day, 4th of July, or Labor Day. I suggest bringing a cushion or a blanket to sit on because you will have a long wait until the bats emerge.

Lower Viewing Area

If you want a close-up view of the emergence and listening to an educational program about bats, this is the place.

The Lower Viewing Area tours are conducted Thursday through Sunday from May through October and the fee is $5 per person ages 4 and up. Children age 3 and under are not allowed at the lower viewing area due to the bat’s sensitivity to noise disturbance. They don’t accept Texas State Parks Pass or the Bluebonnet Pass though. Cash or checks only.

Seats are filled on a first-come-first-served basis with a maximum seating capacity of 70 visitors. They open at 5 p.m. and don’t accept reservations, so arrive at least 30 minutes before they open, especially during holidays and Friday and Saturday. Tour begins approximately one hour prior to bat emergence time. I suggest bringing a cushion or a blanket to sit on because you will have a long wait until the bats emerge.

Special Group Tours 

The tours are conducted at the lower viewing area from Monday through Wednesday evenings, May through October, for organized groups of up to 70 people. Reservations are required, but passports or permits, including the Texas State Parks Pass, are not accepted.

Special group tour fees are as follows: Youth groups:  $1 per person, 35-person minimum, 70-person maximum; non-youth groups: $2 per person, 35-person minimum, 70-person maximum. To schedule a special group tour, please e-mail the park.



  • Location: 10619 Old San Antonio Road, Fredericksburg, TX 78624
  • For the most up-to-date bat emergence information, call the toll-free information line at (866) 978-2287.
  • Email address:
  • Bring drinking water as there’s no water available in the park. Picnic tables are available.
  • Restrooms are only open in the evening during bats seasons (May to October).
  • To minimize disturbance to the bat colony and for your safety, you must stay on the designated trail and you may not approach the tunnel.
  • Camping, pets, and smoking are not allowed.
  • Maybe not such a good place for families with young active kids, even if they are ages 4 and above. Bat disturbed by noise and it is very hard for kids to stay calm and quiet for the duration; starting from when you buy the tickets, listen to the ranger, and watch the bats emerge. (+/- 3 hours).


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